Effects of physical training on peripheral vascular disease: a controlled study

The effects of physical exercise on 8 stage II peripheral vascular disease (PVD) patients were observed after a six-month training program. Doppler velocimetry (including the treadmill test), strain gauge plethysmography, and transcutaneous oxygen pressure were used to quantify the results, which were compared with those obtained in a control group of another 8 stage II PVD patients, under placebo therapy for six months. The results show physical exercise increased the walking capacity, both the pain-free walking time and the maximum walking time. No significant difference was observed in the other parameters studied, in either the exercise patients or the control group.     

Effects of Depot medroxyprogesterone acetate on bone density and bone metabolism before and after peak bone mass: a case-control study

INTRODUCTION: Depot medroxyprogesterone acetate (DMPA; Depo-Provera, Tadworth, UK) contraception is used by more than 9 million women worldwide and has a high usage among teenagers in the United Kingdom and the United States. Previous studies have found that DMPA use is associated with a bone density deficit. OBJECTIVES: This case-control matched study aims to eliminate potential confounding factors, identify whether the effect of DMPA on the skeleton is age specific, and determine the effects of DMPA on hormones and bone turnover. DESIGN/PARTICIPANTS: We measured bone density, bone turnover, and hormones in individually matched case-control pairs of women: 50 pairs aged 18-25 yr and 50 pairs aged 35-45 yr. RESULTS: DMPA use was associated with a 5% bone density deficit at the lumbar spine and hip in women who started DMPA use before age 20 yr but not after age 34 yr. Bone turnover was increased in DMPA users in both age groups. DMPA users had lower estradiol and higher IGF-I than controls, and younger DMPA users had higher dehydroepiandrosterone sulfate than controls. In a multiple regression model, estradiol and IGF-I were associated with bone turnover, but addition of DMPA to the model made the association with estradiol nonsignificant. CONCLUSIONS: DMPA use is associated with a bone density deficit at the spine and hip when used before peak bone mass. DMPA acts on the skeleton mainly through estrogen deficiency.     

Effects of physical training on bone mineral density in fertile women with idiopathic osteoporosis

The aim of this study was to investigate whether moderate physical training can improve the bone mineral density (BMD) in women with idiopathic osteoporosis. Ten pre-menopausal women aged 24–44 years diagnosed with idiopathic osteoporosis were included in the study. The physical training program consisted of three fast 30-min walks plus one or two sessions of 1-h training per week during 1 year at a training centre separate from the hospital. All patients were given supplements of vitamin D and calcium. Bone mineral density was measured in the femoral neck area and the lumbar spine by dual energy X-ray absorptiometry. The measurements were performed at baseline and after 12 months of training and compared with the measurements at the time of diagnosis, 1–3 years before the study. Eight women fulfilled the 12-month training period, and their mean (SD) BMD at start was 0.88 (0.08) g/cm² in the spine and 0.76 (0.13) g/cm² in the femoral neck. The mean spine BMD increase was 0.031 g/cm² (3.5%) after 1 year of training, which was significant (Wilcoxon’s non-parametric test, p = 0.018). The mean increment in BMD in the femoral neck was insignificant, 0.007 g/cm² (0.9%) after the intervention (p = 0.74). However, the bone loss during the 1- to 3-year period from diagnosis to study start was, on average, 0.045 g/cm² or 5.0% in the femoral neck (p = 0.042), thus indicating a positive indirect effect of the intervention. There is no evidence-based therapy for women with idiopathic osteoporosis. It is therefore of importance to elucidate the impact of moderate physical activity in this group of patients. A 1-year training program was sufficient to induce a small but significant change in the spine BMD.     

Fuel-hormone metabolism during exercise and after physical training

In this review the metabolic changes encountered in response to exercise in normal humans are considered in the context of the following categories: (1) fuel utilization and production, (2) hormone secretion, (3) the post-exercise recovery period, (4) effects of physical training on fuels and hormone secretion, and (5) effects of exercise on lipoprotein metabolism.     

Stochastic resonance whole-body vibration training for chair rising performance on untrained elderly: a pilot study

The present randomized controlled pilot study was conducted to determine the feasibility of the study protocol and the effects of four-week-long sessions involving stochastic resonance whole-body vibration (SR-WBV) training on chair rising in elderly individuals. Twenty elderly participants were divided into a SR-WBV group or a sham group. Peak force, rate of force development, rising time, time to stabilization and total time during chair rising performance were investigated. Intraclass correlation coefficients, Mann-Whitney U-tests and Wilcoxon signed-ranked tests were used. Low volume SR-WBV over 12 training sessions might provide a safe treatment method.     

二甲双胍对骨代谢的影响

二甲双胍（metformin,MF）作为一种抗糖尿病药物,在世界范围内被广泛用于治疗2型糖尿病（type 2 diabetes mellitus,T2MD）。近年来,二甲双胍在骨代谢中的作用逐渐得到证实,大量体内外实验表明其对成骨细胞、脂肪细胞等细胞的代谢产生一定影响。已经证实二甲双胍通过激活腺苷酸活化蛋白激酶（adenosine monophosphate activated protein kinase,AMPK）途径促进成骨细胞的分化、矿化以及成骨相关基因的表达。一些临床研究显示,二甲双胍对于糖尿病性骨质疏松（DM-induced bone fragility）产生有益的作用。本文对相关文献加以综述,为二甲双胍在成骨方面的临床研究和应用提供依据和思路。     

肠促胰素对骨代谢的作用

近年来文献相继报道肠促胰素除对糖代谢产生作用外,在骨代谢方面也产生重要作用,主要表现在促进骨形成、抑制骨吸收.其机制尚不明确,可能是通过影响骨钙素基因表达、骨保护素/核因子-κB受体活化因子配体系统和骨硬化蛋白水平.此外,肠促胰素对晚期糖基化终末产物、胰岛素、胰岛素样生长因子、降钙素及血脂的作用也可能影响骨代谢.     

噻唑烷二酮类药物对骨代谢的影响

噻唑烷二酮类（TZDs）药物是核转录因子过氧化物酶体增殖物激活受体γ（PPARγ）的激动剂,是临床上常用的胰岛素增敏剂,用来治疗2型糖尿病等存在胰岛素抵抗的疾病。近年发现TZDs增加女性骨折的危险性。体外及动物实验证实TZDs促进间充质干细胞向脂肪细胞系分化,而抑制其向成骨细胞系分化,减少骨形成,还可能具有促进破骨细胞分化、增加骨吸收的作用,从而导致骨量减少。TZDs还可能通过改变某些激素和细胞因子的水平间接地影响骨代谢。     

二甲双胍对骨代谢的影响

糖尿病患者因骨重塑过程紊乱,使骨折风险明显增加。已证实高血糖和晚期糖基化终末产物对骨组织产生损害作用,糖尿病引起的神经系统和心血管系统合并症也可增加骨折风险。口服降糖药二甲双胍从多种途径影响糖尿病患者的骨代谢,二甲双胍可激活腺苷酸活化蛋白激酶和细胞外信号调节激酶信号通路,导致一氧化氮表达水平和骨形态发生蛋白-2表达量发生变化,影响成骨细胞的增生、分化和矿化。有研究显示,二甲双胍可逆转由高血糖和晚期糖基化终末产物引起的骨损害,并通过促进多潜能骨髓基质干细胞向成骨细胞的分化过程影响糖尿病患者的骨代谢。     

Effects of long-term physical training on body fat, metabolism, and blood pressure in obesity.

Twenty-seven women with varying degrees of obesity were physically trained for 6 mo on an ad lib. diet. Body fat changes were positively correlated with the number of fat cells in adipose tissue. Obese women with fewer fat cells decreased in weight during training whereas women with severe obesity and an increased number of fat cells even gained weight. Blood pressure decreased consistently after training. Blood pressure elevation was not associated with body fat mass, nor was a decrease in blood pressure associated with a decrease in body fat or with pretraining blood pressure level. There were, instead, correlations between decreases in blood pressure on the one hand and initial concentrations and decreases in plasma insulin and triglycerides and blood glucose on the other. These results suggest an association between elevated blood pressure and metabolic variables. The possibility of treating and preventing early essential hypertension with methods that also correct the metabolic derangement, such as diet and exercise, should be given high priority in further research.     

Effects of physical activity on bone remodeling

Physical exercise is recommended to improve bone mass in growing children and decrease bone loss in elderly men and women. However, the specific mechanisms by which exercise influences bone metabolism are still not thoroughly understood. The effect of physical activity on the skeleton is generally evaluated by dual-energy x-ray absorptiometry, which measures bone mineral density. However, a relatively long period is needed to detect even a minor variation in bone mineral density with this technique, limiting its usefulness. Bone biochemical markers that reflect the cellular activities of bone formation and resorption are thus also useful tools, both to monitor the acute effects of exercise on bone remodeling and to investigate the mechanisms of exercise-induced changes in bone mass. This article describes the effects of physical activity on bone remodeling in various types of population. The comparison of sedentary individuals and athletes with many years of high-volume sports practice, for example, has clarified some of the long-term effects of exercise. Moreover, the acute variation in bone cell activities after brief exercise or a training program is here examined. The interpretation of results is difficult, however, because of the many parameters, such as age, that are involved. The various populations are therefore categorized to reflect the biological factors implicated in the modulation of bone marker response during exercise.     

Effects of statins on biomarkers of bone metabolism: a randomised trial.

BACKGROUND AND AIM: Recently, several studies have indicated there may be differences among statins regarding a possible association between therapy and a reduction in risk of fractures. No data from prospective randomised clinical trials designed to assess either biochemical or clinical effects on bone metabolism are yet available. We assayed levels of biochemical markers of bone formation in stored serum samples from a recently completed randomised clinical trial conducted to compare the effects of simvastatin and atorvastatin on the lipid profile of patients with hypercholesterolaemia. METHODS AND RESULTS: This 12-week, randomised, multicenter, open-label study was designed to compare the safety and lipid-lowering efficacy of simvastatin 40 mg or 80 mg with that of atorvastatin 20 mg or 40 mg in 846 hypercholesterolaemic patients. Stored serum samples from this study were analysed to compare the effects of simvastatin and atorvastatin on 2 biomarkers of bone turnover, bone-specific alkaline phosphatase (BSAP), a marker of bone formation, and C-teleopeptide of type 1 collagen (CTx), a marker of bone resorption. Treatment with simvastatin 40 and 80 mg/day, but not atorvastatin 20 and 40 mg/day, led to significant (p < 0.05) reductions in BSAP in both men (4.1-5.4% reduction) and women (4.2-7.4% reduction). In addition, there appeared to be a dose-dependent effect with greater reductions in BSAP seen with the 80 mg dose of simvastatin. Treatment with either 20 mg or 40 mg of atorvastatin had no significant effect on BSAP levels on the groups as a whole or in the gender-specific subgroups. CTx showed a small, but not statistically significant, decrease with simvastatin, again with an apparent dose-related trend. Atorvastatin treatment generally resulted in small, non significant increases in CTx. CONCLUSIONS: The present serum bone biomarker results show that treatment with simvastatin, but not atorvastatin, decreases BSAP and suggest that simvastatin may have a beneficial effect on bone turnover.     

Effects of physical training on coronary risk factors

The effects of exercise training on the known coronary risk factors were studied as an isolated intervention in 39 middle-aged men who were at high risk of coronary artery disease. They were separated into two groups of 20 exercising and 19 control subjects who were carefully matched with respect to age, occupation, coronary risk factors and physical fitness. The exercising subjects participated in a 12 week, supervised training program, but no other attempt to reduce risk factors was made in either group.Exercise training led to a substantial improvement in the physical fitness as determined by increased maximal oxygen uptake, oxygen pulse, ventilation and physical work capacity. Furthermore, there was a significant reduction of systolic blood pressure in the hypertensive subjects who exercised (from 148 to 135 mm Hg, P < 0.01) but not in the hypertensive control subjects (from 150 to 147 mm Hg); the diastolic pressure decreased in both groups. Hypertriglyceridemia also decreased in response to exercise, but there was no significant change in cholesterol levels, obesity, cigarette smoking or psychological profile. A physical training program is therefore valuable as adjunctive therapy in patients at high risk of coronary disease who have hypertension or hypertriglyceridemia.     

全身垂直振动对去卵巢大鼠肝脏和骨组织脂质水平的影响

目的 观察全身垂直振动对去卵巢大鼠肝脏和骨组织脂质水平的影响.方法 36只健康3月龄雌性SD大鼠,体重(250±15)g,按体重分层后随机分为假手术组、去卵巢静止组和去卵巢振动组,每组12只.去卵巢静止组和去卵巢振动组大鼠在麻醉状态下,从背部切除双侧卵巢,而假手术组不切除卵巢,只切除卵巢附近与卵巢等体积的脂肪.去卵巢手术后10 w,去卵巢振动组大鼠开始在垂直振动台上接受振动治疗.振动治疗方案为:频率90 HZ,时间15 min,每天2次,共8 w.实验结束时,用乙醇/氯仿提取肝脏、股骨远端、胫骨近端以及第四腰椎甘油三酯(TG).结果 去卵巢静止组肝脏、股骨远端、胫骨近端以及第四腰椎TG水平均显著高于假手术组,而去卵巢振动组肝脏、股骨远端、胫骨近端以及第四腰椎TG水平均显著低于去卵巢静止组.结论 全身垂直振动能显著降低去卵巢大鼠肝脏和骨组织的TG水平.     

肠道益生菌对骨代谢的影响

研究发现肠道益生菌对骨代谢有正性调节作用,对骨骼健康有益.乳酸菌和双歧杆菌是主要研究对象,肠道益生菌通过多种机制促进维生素D合成,提高矿物质利用度,增加血钙水平,降低甲状旁腺激素水平,增加骨密度和骨矿含量,可能有助于抑制骨质疏松.